lets take an equation say , y = 3x + 5

in this equation if we put values of x independently like x = -2,-1, 0, 1, 2, 3, 4.... Etc then we will get y 's values -1 , 2, 5 , 8, 11, 14, 17....,.etc. According to x 's value. Clearly the variable whose value is chosen by you (independently) is your independent variable, while the variable which adjusts its value accordingly is your dependent variable.

usually we put values of x and then get corresponding y, it means our ind. Variable is x and dependent variable is y.